Thursday 22 April 9.00-10.00pm BBC TWO

Lagos’s version of Venice is Makoko, a slum built on water. Tonight’s programme of this eye-opening series, which explores one of the most extreme urban environments on the planet, continues its journey by taking a trip into the lives of the people who choose to live and work on the waters of Lagos Lagoon.

Fisherman Chubbey lives here in a house built on stilts. With 18 children and five grandchildren to support, he’s become an expert at making money from the most unlikely of places. Whether building a fish pond in the water around him or renting out a spare room which he hasn’t even built yet, he’s always got an innovative scheme on the go. But when his teenage son starts hanging out with a local gang, he faces worries familiar to parents all over the world.

Paul is a saw operator at Ebute Metta, the largest timber yard in West Africa. Much of the wood that goes into building Lagos passes through this place, floated in on enormous rafts, some over a kilometre long. Paul sleeps in the saw mill and dreams of getting his own place in Makoko, but saving enough money takes a long time and the work is dangerous; deadly electric shocks from the machinery are a real fear.

Kissme and Daniel make their living diving for sand at the bottom of the Lagoon and selling it to the building trade. Between them they can fill two dumper trucks a day, collecting every grain with just an old iron bucket, taking it back to shore in a boat with sewn-together rice sacks for sails.

As humans begin to come to terms with an increasingly urban future, this extraordinary series offers unprecedented access and insight into the lives of just a few of the millions of slum dwellers here who are living at the sharp end of the fastest growing megacity in the world.